This invention relates to blends of ethylene/carboxylic acid copolymers with high density polyethylene and inorganic fillers, which blends are useful for making films for skin packaging applications.
Skin packaging is a packaging method involving placing a product on a substrate material, such as paperboard, and draping heated plastic film over the product and substrate. A vacuum is then applied to draw the film down tightly to the board and around the product to make a secure and attractive package. One common application for skin packaging is industrial skin packaging used to protect products in transit. Products as divergent as computer tapes, lamps, service repair kits and table tops may be skin packaged instead of using die-cut corrugated, foam-in-place, foam peanuts and other stabilizing or dunnage materials. Skin packaging offers high throughputs and full visibility to check for tampering or missing components and also allows for quick identification, usually at significant cost reductions.
Low density polyethylene films are often used for skin packaging applications, but skin packaging films of ethylene/acid copolymers have been found to possess faster cycle times, better board adhesion, improved draw and better toughness than the low density polyethylene films. Oddly enough, one drawback of the ethylene/acid copolymer films is their relatively good optical properties since they more readily show the relatively unattractive packaging board used for the skin packaging of industrial items. Additionally, the industrial items themselves are often relatively unattractive. Thus, a method for affecting the optical properties of the ethylene/acid copolymer films, while not adversely affecting the desirable properties of such films, such as adhesion, was desired.